Conventionally, insulated electric wires that have a configuration such that an insulator that covers a conductor is made from a polyvinyl chloride resin for the purpose of obtaining flexibility are in widespread use. Recently, insulated electric wires that have a configuration such that an insulator that covers a conductor is made not from a polyvinyl chloride resin but from a composition containing a polyolefin resin such as polyethylene, polypropylene and alpha-olefin principally, and a flame retardant additionally have been proposed (see Japanese Patent Application Laid-Open No. 2002-309048, for example,).
The insulated electric wire disclosed in Japanese Patent Application Laid-Open No. 2002-309048 has a configuration such that an insulator that covers a conductor is made from a specific resin composition having a flexural modulus of not more than 2,000 MPa for the purpose of obtaining flexibility.